Fuze for Stun Grenade

ABSTRACT

A stun grenade includes a fuze assembly secured to a housing adjacent gas outlet ports. The fuze assembly includes a fuze body having contact surfaces located in the flow path of the gas from the outlet ports so that gas flowing from the outlet ports impinges on the contact surfaces. The contact surfaces of the fuze body extend at an angle of no more than about 50 degrees to the first direction.

RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.Provisional Application No. 61/158,673, filed Mar. 9, 2009, titledImproved Distraction Device Fuze, the entire disclosure of which isincorporated by reference.

BACKGROUND OF THE INVENTION

Explosive grenades are designed to cause fragmentation of most or all oftheir parts, including the housing and the fuze body, so as to inflictmaximum damage on a person who is nearby when the device explodes.

More recently, a class of grenades have been designed that are variouslyknown as stun grenades, or flash-bang devices. These devices are notintended to cause physical harm, but rather are intended to temporarilystun a person with a loud sound, a bright flash, and a pressure wave.Such devices are intended to be activated near the person and thus mustnot fragment or they could cause serious harm to the person.

Many of these less lethal devices use carry-over parts fromfragmentation grenades, simply replacing the explosive charge with adifferent charge. One part that has to date been carried over, withoutchange, is the fuze body. For example, U.S. Pat. No. 5,654,523, theentire disclosure of which is hereby incorporated by reference,describes a stun grenade that includes a grenade body having a pluralityof vents on one end, adjacent to a fuze body that supports the fuze ofthe device. The fuze body includes portions that support the releaselever of the device. The outlet vents of the grenade body direct some ofthe byproducts onto the fuze body wings. The force that is transmittedinto the fuze body by the explosion byproducts can undesirably cause thefuze head to separate, or the fuze body otherwise to fragment,consequences that could undesirably result in injury to a nearby person.The present invention addresses this problem.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the invention will become apparent to one ofordinary skill in the art to which the invention pertains from a readingof the following description together with the attached drawings, inwhich:

FIG. 1 is a longitudinal sectional view of a stun grenade in accordancewith a first embodiment of the invention;

FIG. 2 is an enlarged view of a portion of the device of FIG. 1illustrating a fuze assembly that is part of the device;

FIG. 3 is a perspective view of a fuze body that forms part of the fuzeassembly;

FIG. 4 is a view similar to FIG. 1 of a prior art stun grenade;

FIG. 5 is an enlarged schematic view of a portion of the fuze body ofthe stun grenade of FIG. 1; and

FIG. 6 is a view similar to FIG. 5 of the fuze body of the prior artstun grenade of FIG. 4.

DETAILED DESCRIPTION

This invention relates to stun grenades, and in particular relates to astun grenade with a fuze body that is configured to minimize thepossibility of separation or fragmentation. The invention is applicableto stun grenades of varying and different configurations. Asrepresentative of the invention, FIG. 1 illustrates a stun grenade 10constructed in accordance with a first embodiment of the invention.

The stun grenade 10 includes a housing 12. The housing 12 includes amain body 14 having a cylindrical configuration centered on alongitudinal central axis 16 of the device 10. The main body 14 definesa cylindrical chamber 18 for receiving a cartridge 20 containing acharge 22 such as an explosive mixture that when activated generatesexplosion byproducts including gas under pressure as well as a brightflash and a loud bang. A bottom wall 24 closes one end of the chamber 18and a top wall 26 the other end of the chamber.

The top wall 26 has a plurality of outlet ports 30 communicating withthe chamber 18. The outlet ports 30 are disposed in a circular arraycentered on the axis 16. A collar 32 is screwed into the top wall 26.The collar 32 has a threaded central opening 34.

The stun grenade 10 includes a fuze assembly 40 for activating thecharge 22. The fuze assembly 40 is secured to the collar and includes afuze body 50. The fuze body 50 supports a fuze lever or release lever52. A pin 54 is received in an opening 56 in the fuze body 50; the pinmust be removed before the lever 52 can be released to activate thedevice 10.

The fuze body 50 is preferably made from cast zinc, but can be made fromanother material. The fuze body 50 includes an externally threaded,hollow, cylindrical mounting post 58 that screws into the collar 32. Thefuze body 50 also includes a fuze head 60, which is the portion of thefuze body that extends axially outward of the collar 32, in a directionaway from the mounting post 58. The fuze head 60 includes a centrallylocated main body portion 62 that is co-axial with the mounting post 58.A radially extending flange 64 is located at the area between the mainbody portion 62 and the mounting post 58.

The fuze head 60 includes two wings 70 that extend outward from the mainbody portion 62. The wings 70 are planar in configuration and extendparallel to each other, on opposite sides of the axis 16, in a directionaway from the axis. The wings 70 extend parallel to a radius locatedmidway between them. Each wing 70 includes an opening 72 that receivesthe locking pin 54, which extends between the two wings. Each wing 70also includes an opening 74 for receiving and supporting the fuze lever52.

When viewed in elevation, as in FIG. 5, each wing 70 can be seen to havea generally triangular edge portion 76, or lever support portion, thatcontains the openings 72 and 74 that support the pin 54 and the lever52. The edge portion 76 is disposed radially outward of the mountingpost 58, and of the main body portion 62, and of the flange 64 of thefuze body 50.

The wings 70 are formed with a relatively thin wall section. Forexample, in one embodiment, the wings 70 are 0.08 inches in thickness,extend about 0.4 inches radially outward from the main body portion 62,and project about 0.8 inches axially from the flange 64.

When the charge 22 is activated, byproducts including gas under pressureflow from the outlet ports 30, in a flow path 80 that extends in a firstdirection as indicated by the arrows 82, a direction generally parallelto the axis 16. The wings 70 are the portion of the fuze body 50 that islocated axially above the outlet ports 30 of the device 10, in the flowpath 80. The wings are relatively far out from the axis 16 of the device10, and thus have a relatively high moment arm that could impart asignificant twisting force on the fuze head 60, tending to cause thefuze head to twist upward and possibly separate from the other parts ofthe fuze body 50 including the threaded mounting post 58. It istherefore desirable to minimize forces applied to the wings by explosionbyproducts flowing from the outlet ports 30.

To this end, the fuze body 50, and specifically the wings 70, isdesigned with minimal exposure to the force of such byproducts.Specifically, each wing 70 has a first edge surface 90 that extends fromthe outer edge of the flange 64, axially and radially outward from theflange, to a location just outside of the opening 72 that supports thepin 54. In one embodiment, this first edge surface 90 extends at anangle “α”(FIG. 5) which is most preferably about 31 degrees from thefirst direction 82. In other embodiments, this angle can be in the rangeof from 20 degrees to 50 degrees, and is preferably in the range of from20 degrees to 40 degrees. Because the edge surface 90 lies at arelatively small angle to the first direction 82, its exposure to theforce of the gases flowing from the output ports 30 is lessened.

Each wing 70 has a second edge surface 92 that extends from the firstedge surface 90, axially outward and radially inward, to a location justoutside of the opening 74. This second edge surface 92 merges, via aradius surface 94, with a third or outer edge surface 96 of the wing 70,which extends perpendicular to the axis 16 and forms the axiallyoutermost edge surface of the wing and of the fuze body 50.

The amount or portion of the wings 70 that is located axially in linewith the outlet ports 30 and relatively far from the axis 16 is thusminimized. Instead, the wings 70 include only the minimum amount ofmaterial needed to provide support for the lever 52 and the pin 54, viathe openings 74 and 72, respectively. As can be seen from FIG. 5, thewings 70 are free of surface portions that are directly in the flow path80 and that extend at an angle of more than about 50 degrees, orpreferably more than about 40 degrees, to the first direction 82. Inaddition, the surfaces impinged upon by the gas flowing from the outletports 30, because they are angled upward from the flange, are fartheraway from the outlet ports than in the prior art design (FIGS. 4 and 6).The amount of wing material that is relative relatively far from theaxis 16 is minimized. As a result, force exerted on the wings 70 by thegas flowing from the outlet ports 30 is minimized, thus minimizing thepossibility of separation or fragmentation of the fuze body 50. Thefunction of the lever 52 and pin 54 are retained.

In contrast, FIGS. 4 and 6 illustrate a prior art device 100 thatincludes a fuze body 102 having wings 104 with a large portion 106disposed directly over the outlet ports 108 of the device. The wings 104have a first edge surface 110 that extends radially outward, in adirection perpendicular to the axis 112. The wings 104 of the prior artdevice 100 are thus subject to a substantially larger amount of forcefrom the gases flowing from the outlet ports 108.

In accordance with another feature of the invention, the wall thicknessof the mounting post 58 is increased as compared to the wall thicknessin the prior art fuze body. The same inner diameter is maintained, toaccommodate the fuze, resulting in a larger outer diameter for themounting post. For example, in one fuze body 50 that is an embodiment ofthe invention, a nominal mounting post wall thickness of 0.225 inches isprovided, as compared to a nominal wall thickness of 0.116 inches in theprior art device. This thickened cross-section provides a strongerconnection with the collar 32, and means that the fuze body 50 is lesslikely to bend or separate the fuze head 60, at the location of theflange 54, in response to forces impinging on the wings 70 upon gasgenerating material activation.

In accordance with another feature of the invention, the fuze bodymounting post 58 is provided with a finer thread convolution 120 (FIG.5) as compared to the thread convolution used in the prior art fuzebody. For example, in one fuze body 50 that is an embodiment of theinvention, a 9/16-12 thread is used, as compared to the coarser threadthat is used in the prior art device. This results in the fuze bodymounting post 58 retaining a greater amount of material when the threadis cut, providing a stronger connection with the collar 32, to againminimize the possibility of the fuze body 50 bending or breaking inresponse to forces impinging on it upon gas generating materialactivation. In addition, the thread roots on the fuze mounting post 58are filleted to reduce stress concentration on the threads.

1. A stun grenade comprising: a housing having a chamber centered on anaxis and containing an activatable gas generating material; the housinghaving outlet ports for directing gas out of the chamber, uponactivation of the gas generating material, along a gas flow path thatextends in a first direction generally parallel to the axis; a fuzeassembly for activating the gas generating material, secured to thehousing adjacent the outlet ports; the fuze assembly including a fuzebody having contact surfaces located in the flow path of the gas fromthe outlet ports so that gas flowing from the outlet ports impinges onthe contact surfaces; the contact surfaces of the fuze body extending atan angle of no more than about 50 degrees to the first direction.
 2. Astun grenade as set forth in claim 1 wherein the contact surfaces extendat an angle to the first direction that is in the range of from about 20degrees to about 40 degrees.
 3. A stun grenade as set forth in claim 2wherein the contact surfaces extend at an angle to the first directionthat is about 31 degrees.
 4. A stun grenade as set forth in claim 1wherein the fuze body comprises two planar wings each having an outeredge surface presented at least partially toward the outlet port, theouter edge surfaces of the wings constituting the contact surfaces ofthe fuze body, the outer edge surfaces of the wings extending at anangle of no more than about 50 degrees to the first direction.
 5. A stungrenade as set forth in claim 4 wherein the outer edge surfaces of thewings extend at an angle of about 30 degrees to the first direction. 6.A stun grenade as set forth in claim 1 wherein the fuze body includes amain body portion located radially inward of the outlet ports, the mainbody portion of the fuze body supporting the contact surfaces of thefuze body at a location radially outward of the main body portion and inthe flow path of gas from the outlet port.
 7. A stun grenade as setforth in claim 1 wherein the fuze body includes a threaded mounting postscrewed into the housing to secure the fuze assembly to the housing, themounting post including a fine thread convolution with filleted roots.8. A stun grenade as set forth in claim 1 wherein the fuze body includesa threaded mounting post screwed into the housing to secure the fuzeassembly to the housing, the mounting post including a thick walledcross section.
 9. A stun grenade comprising: a housing having a chambercentered on an axis and containing an activatable gas generatingmaterial; the housing having outlet ports for directing gas out of thechamber, upon activation of the gas generating material, along a gasflow path that extends in a first direction generally parallel to theaxis; a fuze assembly for activating the gas generating material,secured to the housing adjacent the outlet ports; the fuze assemblyincluding a fuze body having a mounting post threaded into the housingto secure the fuze to the housing; the fuze body having a lever supportportion located axially and radially outward of the post and projectingover the outlet port; the lever support portion being free of gascontact surfaces that extend at an angle of more than about 50 degreesto the first direction; the mounting post having a fine pitch threadconvolution that is threadedly engaged with a fine pitch threadconvolution on the housing to secure the fuze to the housing, the finepitch thread convolution on the fuze body threaded post having afilleted root diameter.